Ian Harte has revealed he immediately stopped a drinking session and sobered up after Roy Keane said "I'm gonna f***ing smash you!" ahead of a crunch Premier League clash.
The two Irishman were international teammates during a time where Harte's Leeds United were trying to challenge the domestic dominance of Manchester United.
The Whites were on the rise, but needed to win clashes against the Red Devils to underline their title credentials.
With Ireland the pair put their differences aside and often socialised together.
Harte recalls a drinking session which ended with a brutal put down from Keane, despite also calling him a "great lad", which saw the Leeds star cut his evening short.
Have Your Say! Do Man Utd need to make some signings in January? Tell us your prediction here.
"I was at Levante for three seasons and then I signed with Sunderland for one year," Harte tells the Players Lounge section of FourFourTwo.
"I didn't play much there but it was one of those things. I respected Roy as a player but, as a manager, he could have done things differently.
"Back when we both played for Ireland, we'd sometimes go for a drink together. After one night out, we got back to the hotel - Leeds were due to play Manchester United on the Saturday.
"Roy turns around and says, 'Hartey, you're a great lad. But when we play you at the weekend, I'm gonna f***ing smash you!' I sobered up straight away and went to bed.
"I love Roy though, I've got so much respect for him."
Harte spent almost a decade at Elland Road, playing 288 times for the Yorkshire outfit before leaving after their relegation in 2004.
The Irishman, who played at left-back, was known as a deadball specialist.
He played in the Premier League during the same time period as Keane's United's teammate David Beckham.
The global megastar became renowned for his curling free-kicks and still holds the Premier League record for the amount scored.
Beckham notched 18 to Harte's 10 but the former Leeds star believes he was certainly a match.
He claimed: "I'd watch Roberto Carlos and think, 'What a left-back! How good is he at free-kicks?' Beckham was unbelievable too.
"People never check but I'd like to see the stats of how many they took compared to me. I reckon my numbers are near the top.
"I mean, David Beckham might have had 200 more free-kicks than me and scored 20 - I might have only had 70 and scored 15. I don't know."